1. Field of the Invention
Embodiments of the invention generally relate to methods and apparatus for improving safety features of equipment used in the oil and gas industry. More specifically, embodiments of the invention relate to a secondary safety device for use on elevators utilized to move casing, tubing, sucker rods, or other tubular members and/or circular tools, in the oil and gas industry.
2. Description of the Related Art
An elevator is a device that is used to clamp or grip tubular members or circular tools, such as casing, tubing, drill pipe, or sucker rods, utilized in a drilling operation or rig work-over operation. A conventional elevator includes two arc-shaped members that are hingedly coupled on one end to open and close in a clamshell manner. The members may be closed to define a center hole that receives the circular tool, and opened to allow the circular tool to move into or out of the center hole. In the closed position, a primary safety latch is used to secure the free ends of the two arc-shaped members thereby preventing the two arc-shaped members from opening unexpectedly.
Primary safety latches on conventional elevators typically utilize a secondary safety mechanism to prevent the primary safety latch from opening accidently. The secondary safety mechanism may include a pin, such as a rod or a large cotter pin, that may be inserted into a hole or holes that cross the primary safety latch and prevent the primary safety latch from opening. When the elevator is to be opened, the pin is removed from the holes, which allows the primary safety latch to be positioned to allow the arc-shaped members to open.
The conventional secondary safety mechanism design has at least the following drawbacks. Use of the secondary safety mechanism typically requires the use of two hands to properly align the holes and install the pin into the holes. The hole/pin alignment and installation process may extend the time needed to properly secure the primary safety latch. Additionally, a hazardous condition is created as the operator has both hands in proximity to pinch points associated with the elevator. Further, the pin must be safely stored when not in use. Some conventional elevators include a storage hole for the pin. However, inserting the pin into the storage hole adds additional operator time. Other conventional elevators utilize a cable or small chain attached to the pin to prevent loss of the pin when not in use. However, the cable or chain may be damaged and the pin may be lost. Additionally, the cable or chain securing the pin may create a hazardous condition by potentially snagging or otherwise injuring an operator.
What is needed is an improved secondary safety lock mechanism for safely and efficiently locking a primary safety latch.